use Modern::Perl;
use Data::Dumper;

my $a = 'a,b,c,d,,,,,,,';

my @col = $a =~ /([^,]+)/gi;

say Dumper \@col;

##</code><code>##

$VAR1 = [
          'a',
          'b',
          'c',
          'd'
        ];

##</code><code>##

use Modern::Perl;
use Data::Dumper;

my $a = 'a,b,c,d,,,,,,,';

my @col = ( split ',', $a, )[ 0 .. 3 ];

say Dumper \@col;

##</code><code>##

$VAR1 = [
          'a',
          'b',
          'c',
          'd'
        ];